Cerebrospinal Fluid Pharmacokinetics of Tigecycline in Lumbar and Ventricular Compartments After Lumbar Intrathecal Administration: A Three-Patient Case Series.

Background: Lumbar intrathecal administration of tigecycline has been increasingly used as a salvage treatment for multidrug-resistant (MDR) intracranial infections. However, whether lumbar administration can generate adequate tigecycline exposure in ventricular cerebrospinal fluid (CSF), remains insufficiently characterized. Case Presentation: We retrospectively analyzed three patients with intracranial infections who received 5mg tigecycline through a lumbar drainage catheter and had concurrent lumbar and ventricular CSF access. The underlying conditions were postoperative primary meningioma, brain abscess, and traumatic cerebral contusions, respectively. The identified pathogens included Conclusion: In this three-patient case series, 5 mg lumbar intrathecal tigecycline achieved measurable but markedly attenuated ventricular CSF exposure, with substantial interpatient variability, and no predefined neurotoxic adverse events were documented in this small series. Lumbar intrathecal administration may be considered when ventricular administration is unavailable or undesirable, with individualized assessment and therapeutic drug monitoring where feasible.